WO2014206542A1

WO2014206542A1 - Compensating oscillation device

Info

Publication number: WO2014206542A1
Application number: PCT/EP2014/001664
Authority: WO
Inventors: Carsten ROSENHAGEN; Ingo RÜHLICH
Original assignee: Aim Infrarot-Module Gmbh
Priority date: 2013-06-26
Filing date: 2014-06-18
Publication date: 2014-12-31
Also published as: JP2016525203A; IL242994B; EP3014142A1; JP6495260B2; US20160153512A1; ES2738314T3; DE102013011928A1; US10190650B2; SI3014142T1; EP3014142B1

Abstract

The invention relates to a compensating oscillation device (2) for a linear piston system (1). The compensating oscillation device comprises a housing (4), at least two coupling elements (10), and a centrifugal mass (8), which can be deflected along an axis (7) by means of each coupling element (9) and which is coupled to the housing (4). Each coupling element (9) is fastened to the housing (4) at at least one fastening region (26, 28) and to the centrifugal mass (8) at at least one connecting region (18, 20). According to the invention, on each of the at least two coupling elements (9), the at least one connecting region (18) to the centrifugal mass (8) is radially closer to the axis (7) than the at least one fastening region (26) to the housing (4), and the centrifugal mass (8) is arranged between two coupling elements (9) in the axial direction in the idle state. The invention further relates to a linear piston system (1), comprising a piston (40), which is supported in such a way that the piston can be moved linearly, and comprising such a compensating oscillation device (2).

Description

Compensation oscillating device

The invention relates to a Ausgleichsschwingvorrichtung for a linear piston system, comprising a housing, at least two coupling members, and a coupled via each coupling member along an axis pivotally coupled to the housing flywheel, each coupling member at each at least one mounting region on the housing and at each at least one Anbin- dungsbereich attached to the flywheel. The invention further relates to a linear piston system with such a compensating vibration device.

High-performance infrared sensors achieve the desired electro-optical properties, such as the signal-to-noise ratio, usually only at low temperatures well below the ambient temperature. The temperatures are usually in a range between 80K and 200K. For the cooling of such sensors cryocooler are preferably used, which usually work after the Stirling process. In this process, a refrigerant, usually the working gas helium, undergoes a periodic pressure oscillation. The pressure change can be achieved by a compressor with one or more moving working pistons. A relevant drive mechanism of the piston is in particular a linear drive. The compressors used are valveless, so that the frequency of the engine or piston movement corresponds to the frequency of the pressure change. Due to the axial movement of the linear motor (s) together with the driven pistons, forces are produced which are transmitted from the housing of the compressor via the mechanical attachment to a connected system. In the case of two counter-rotating pistons, the forces manifesting as vibrations are due to more or less pronounced differences in the two drive halves with respect to characteristics such as engine efficiency, friction or mass. dingt. In single-piston compressors, the vibrations can be very pronounced because there is no balance of forces between two halves of the drive.

In order to reduce the vibrations caused by the piston movement, a passive balance oscillator, which is elastically coupled to the piston or its housing, is often used in a linear piston radiator, which is intended to compensate for the vibrations of the piston movement.

No. 5,895,033 A describes a compensation oscillating device for a linear piston system in which an annular flywheel mass is coupled at its inner diameter to a central retaining bolt via two blade or diaphragm spring arrangements, wherein the piston movement preferably takes place along the ring axis. The retaining bolt may in this case be mounted outside the housing of the piston or mounted on the inner wall of a capsule, which is to be screwed onto the housing of the piston. To increase the stability of the arrangement may also be provided one or more coil or coil springs, which are clamped between the flywheel and the housing wall or between the flywheel and a flange at the free end of the bolt.

In an arrangement outside the housing, the annular flywheel is disadvantageously exposed to possible shocks that may affect the vibration-damping effect of the mass. In addition, due to the annular mass distribution and the radial coupling to the retaining bolt in the case of shocks given the undesirable possibility that the vibrations no longer run only along the ring axis, but are tilted against it. Again, this is disadvantageous in terms of the operation of the Ausgleichsschwingvorrichtung.

Therefore, it may also be disadvantageous in a very compact design to protect the flywheel by any additional components such as another spring element or a capsule from shocks.

In US 2002/0121816 A1 a Ausgleichsschwingvorrichtung is called, in which a rod, at the ends dumbbell-like two masses are attached, are coupled via two spring arrangements, which act on the rod between the two masses of inertia, to a housing. Between the two spring assemblies, magnetizable sheets are mounted on the rod and Inserted magnets, so that in this way a linear motor is formed, via which the Ausgleichsschwingvorrichtung can be actively operated. A passive operation of the Ausgleichschwschwvorrichtung is not mentioned.

In DE 10 2009 023 971 A1 a Ausgleichsschwingvorrichtung for a linear piston system is shown, in which a flywheel is coupled via a spring arrangement directly to a rigidly connected to the piston rod and is connected via further spring arrangements to the housing of the linear piston system. For the function of the connection to the piston via the rod is essential, which in structural changes that affect only the piston, a realignment of the Ausgleichsschwingvorrichtung requires a total.

The invention is therefore an object of the invention to provide a passive Ausgleichsschwingvorrichtung in which the flywheel is compact and simple construction as insensitive to shocks and shocks. Furthermore, an advantageous application for such a compensating device is to be specified.

The former object is for a Ausgleichsschwingvorrichtung for a linear piston system, comprising a housing, at least two coupling members, and about each coupling member along an axis deflectably coupled to the housing flywheel, each coupling member at each at least one mounting portion on the housing and at each at least one connection region is attached to the flywheel, according to the invention solved in that the at least two coupling members each of the at least one connection region to the flywheel radially closer to the axis than the at least one mounting portion to the housing, and that the flywheel is arranged in the idle state in the axial direction between two coupling members ,

The mental starting point here forms a flywheel, which can be excited along an axis to linear vibrations. The axis is defined here by the center of gravity movement of the flywheel, and coincides in the case of a substantially annular mass distribution with the ring axis.

An arrangement of the flywheel at rest between two coupling members to mean that the Ausgleichsschwingvorrichtung two Coupling members which are axially spaced from each other, and between the attachment regions at least the substantial mass fraction and at least the essential volume fraction of the flywheel is concentrated. In particular, in this case also a mass distribution is included, which extends in the vicinity of the axis on both sides of a connection region of a coupling member, for example by a device for connection such as a screw or a flange.

In a first step, the invention proceeds from the fact that, by coupling the flywheel to the housing inwardly towards the axis, undesirable tilting vibrations about a further axis perpendicular to the desired vibration axis can be excited due to the off-axis mass concentration. A change in the geometry of the flywheel while maintaining the coupling inwards to the axis could reduce the number of possible excitation modes, but does not effectively suppress remaining vibrations due to the pendulum-like arrangement. A possible increase in the rigidity of the coupling, e.g. By means of increased spring constants when coupled via spring elements, the desired oscillation would also be adversely affected by a change in the resonant frequency and can therefore not be effective in order to avoid undesired vibrations.

In a second step, the invention recognizes that the oscillation axis can be stabilized against possible tilting by connecting the flywheel mass in at least one area on the outside. An external connection should mean that for a coupling member attachment to the housing radially further out than a connection of the corresponding coupling member to the flywheel. The flywheel is thus held by the respective coupling members radially from the outside on the oscillation axis. An external connection of a coupling member to the flywheel also allows at least in the immediate vicinity of the relevant connection area an axis nearer mass concentration compared to a centrally coupled annular mass distribution. Characterized in that forces are received in each case in a radial direction of a coupling member fixed off-axis, the connection region can be arranged on the outside of the flywheel, no coupling is required near the axis in the corresponding radial direction. Thus, in the area concerned, mass fractions can be arranged closer to the oscillation axis. Due to the higher con- Concentration of the mass in the vicinity of the oscillation axis, it is additionally stabilized against possible tilting during vibrations.

Such a connection by means of a plurality of coupling members in this case allows a particularly an axle-stable coupling of the flywheel. It is advantageous here that the center of mass of the flywheel is arranged in the idle state in the axial direction between two coupling members. As a result, the oscillation axis is particularly effectively protected against tilting in the direction of the force acting on the coupling members. In particular, in this case, both coupling members may each be rotationally symmetrical, so that the force acting on each of the two coupling members is substantially radially symmetrical, and thus tilting of the oscillation axis in any azimuthal direction is particularly difficult.

In a third step, the invention recognizes that, moreover, an off-axis attachment of the coupling elements can be configured such that the fastening region on the housing protects the flywheel from shocks. Due to the fact that the fastening region of the corresponding coupling member to the housing is spaced farther from the axis in the radial direction than the connection region to the flywheel mass, the housing can surround the flywheel mass radially from the outside in an environment of the corresponding fastening region and thus from a specific spatial direction protect. In particular, in this case, the option of a complete outside coupling is possible, that is, each attachment region of a coupling member to the flywheel is radially closer to the axis than any attachment region of the corresponding coupling member to the housing. In this case, a wall of the housing completely surround the flywheel in the azimuthal direction and thus protect against essentially radial contacts or direct impacts from any direction.

It proves to be advantageous if each coupling member essentially rigidly couples the flywheel in a plane perpendicular to the axis. By limiting radial degrees of freedom, the oscillation axis can be effectively stabilized.

In a favorable embodiment, each connection region of a coupling member to the flywheel is located radially closer to the axis than each attachment region of the corresponding coupling member to the housing. Prefers This arrangement may apply separately for each existing coupling member. In particular, in this case, the respective coupling members may be arranged annular disk or spoke shape around the flywheel mass. By said arrangement, the flywheel is externally connected to respective coupling members and thus held by these from the outside on the oscillation axis, which is thus particularly stable against tilting. Moreover, with a complete outside coupling of the flywheel mass distribution can be massively concentrated around the axis except for possible holes for connection. As a result, the flywheel is additionally carrier against suggestions of unwanted tilting vibrations.

Advantageously, each coupling member is connected to the or each connection area by welding and / or screws and / or gluing and / or clamping (in particular by a resilient bias in the parts involved or in an additional spring element) to the flywheel, and / or attached to the or each attachment area by welding and / or screws and / or gluing and / or clamps to the housing. By a compound of the type mentioned between coupling member and housing or between the coupling member and flywheel, a coupling member in the radial and azimuthal direction can be fixed in a simple manner, while the axial elasticity is ensured.

Conveniently, each coupling member is formed as an elastic spring element in the axial direction. Due to the design of each coupling member as a spring element, a desired axial elasticity can be adjusted particularly easily via the spring rate.

As low, it turns out, if the housing and / or the flywheel are formed substantially rotationally symmetrical. A substantially rotationally symmetrical shape should include unavoidable manufacturing inaccuracies and axial bores necessary for mounting, connection or fastening, which lead to a deviation from a rotationally symmetrical shape in detail. In such an embodiment of the flywheel, the vibration axis has a high stability against tilting due to the lack of azimuthal preferential direction. A corresponding adaptation of the shape of the housing to the shape of the flywheel simplifies the attachment of a coupling member to the housing and its connection to the flywheel. In particular, a rotationally symmetric Housing the flywheel effectively shield from shock from any radial direction.

Preferably, the axial length of the flywheel decreases monotonically with increasing radial distance from the axis. The axial length of the flywheel is to be understood as meaning the distance between two points which lie opposite each other on the axially outermost surfaces of the flywheel at the same radial distance and at the same azimuth angle with respect to a reference point, wherein these points are to be chosen such that they do not coincide possible axial holes for mounting elements coincide. As a result, the mass distribution is concentrated as close to the axis, which gives the oscillation axis increased inertia against suggestions of unwanted tilting vibrations.

Conveniently, each coupling element is essentially, that is, except for unavoidable manufacturing inaccuracies and for mounting, connection or attachment necessary configurations such. axial bores, rotationally symmetrical. This includes in particular an embodiment in the form of a spoke disk or an annular disk with spiral cuts. By a rotationally symmetrical shape radial forces are absorbed as uniformly as possible by each coupling member, and thus the vibration axis effectively stabilized against shocks.

In a further advantageous variant, each coupling element couples in the rest state of the flywheel in the radial direction of the housing, that is, each coupling element is in the idle state of the flywheel substantially perpendicular to the axis. In this way, a coupling member can absorb radial forces on the flywheel particularly effective and thus keep the desired vibration axis stable.

As further favorable, it turns out that the flywheel is surrounded in the radial direction by the housing and the housing is closed in an axial direction with a lid. Thus, the flywheel has a mechanical protection of the moving vibrator from external contact, at the same time a compact design is possible.

The second object is achieved according to the invention by a linear piston system, which comprises a linearly movably mounted piston and a compensating vibration device of the type described above. The advantages of Ausgleichsschwingvorrichtung and its developments can be analogously transmitted to the linear piston system.

In this case, the piston in the housing of the compensating oscillation device is preferably mounted so as to be movable in the axial direction, relative to the axis of the compensating oscillation device. In particular, in this case, the axes of the center of gravity movements of piston and flywheel can coincide. An arrangement of pistons and flywheel in the same housing allows a particularly compact design, in which moreover the flywheel can be effectively protected by the wall of the housing from shocks. In particular, a coaxial bearing of the piston and the flywheel, ie an arrangement in which the center of gravity of the piston and the center of gravity of the flywheel can move on the same axis, provides for an advantageous compensation of the vibration generated by the piston movement by the compensating vibration device.

The piston in the housing is preferably designed as a working piston of a compressor. Said balancing device is particularly suitable for compensating the forces occurring during the movement of a compressor piston. In other words, the balancing device is used for a linear compressor system as used for cooling high performance infrared sensors.

An embodiment of the invention will be explained in more detail with reference to a drawing. Showing:

Fig. 1 shows a linear piston system with a coaxially arranged Ausgleichsschwingvorrichtung in cross-sectional view, and

Fig. 2 is a Ausgleichsschwingvorrichtung with arranged on the housing cover in cross-sectional view.

In Fig. 1, a linear piston system 1 is shown with a balancing device 2 in cross section. In the exemplary embodiment, the linear piston system 1 is designed as a single-piston cryocooler. The housing 4 of the compensating vibration device 2 is firmly joined to the outer housing 6 of the linear piston system 1. In the housing 4 a rotationally symmetrical with respect to the axis 7 flywheel 8 is mounted axially movable, which is a substantially trapezoidal having shaped generating surface. The flywheel 8 is coupled via two coupling members 9, which are designed as diaphragm springs 10, 12, to a housing 4 belonging to the cylinder cap 16. Here, the membrane springs 10, 12 are connected in their respective attachment regions 18, 20 via two nested fixing screws 22, 24 to the flywheel 8. At the attachment regions 26, 28, the membrane springs 10, 12, a circumferential ring 30 in the cylinder cap 16 enclosing from both sides, attached to the housing 4. In the idle state of the flywheel 8, the diaphragm springs 10, 12 are substantially perpendicular to the axis 7, so that the connection areas 18, 20 of the diaphragm springs 10, 12 are radially closer to the flywheel 8 on the axis 7 than the attachment areas 26, 28 of FIG Diaphragm springs 10, 12 to the housing 4. For deflectability of the flywheel 1 in the direction of the axis 7, a recess 32 for the fixing screw 22 is provided in the housing 4.

In the outer housing 6 of the linear piston system 1, a piston 40 is movably inserted in a cylinder 42 along the axis 7. The piston 40 is connected via a retaining bolt 44 with a coil spring 46, which is connected in the axial direction via a further retaining pin 47 with the housing 4 of the compensating vibration device 2. The piston 40 is pressed by the coil spring 46 into a chamber 48 in the cylinder 42. Around the cylinder 42 is located in the outer housing 6, an annular gap 50. In this engages a connected to the piston 40 at the opposite end of the chamber 48 cylindrical wall 52 on which in the annular gap 50, a circumferential magnetized ring 54 is placed. Surrounding this magnetized ring 54, a number of magnetic coils 56 are incorporated in the outer housing 6. The magnetized ring 54 and the magnetic coils 56 are configured to drive the piston 40 to linear oscillations along the axis 7. The chamber 48 is connected via a channel 58 with a cold finger not shown in detail in the drawing. The piston 40 is designed as a working piston of a compressor.

Vibrations, which are transmitted by the periodic movement of the piston 40 on the outer housing 6 and thus on the housing 4 of the Ausgleichsschwingvorrichtung 2 can now be at least partially compensated by the connection via the diaphragm springs 10, 12 of the flywheel 8 of the Ausgleichsschwingvorrichtung 2. The radially outer side attachment of the diaphragm springs 10, 12, so the arrangement radially further outside lying mounting portions 26, 28 and radially further inside Anbin- training areas 18, 20 to the flywheel 8, this ensures a high stability of the axis 7 against possible shocks. This is reinforced by the concentration of the mass distribution of the flywheel 8 about the axis 7 and a concomitant, further improved inertia against tilting.

In Fig. 2 an alternative to Fig. 1 compensating vibration device 2 is shown with a cover 4 arranged on the housing 60 in cross section. The flywheel 8 is in turn coupled via diaphragm springs 10, 12 to the cylinder cap 16 of the housing 4. Along the axis 7, the housing 4 is firmly joined to the outer housing 6 of a piston, not shown in detail in the drawing. The cover 60 is seated on the housing 4 on the cylinder attachment, the connection to the outer housing of the piston 40 with respect to the flywheel 8 opposite lying on. Facing the flywheel 8, a recess 62 for the fixing screw 24 for deflectability of the flywheel 8 is provided in the cover 60. By the cover 60, the flywheel 8 is protected from external contact.

LIST OF REFERENCE NUMBERS

1 linear piston system

2 leveling device

4 housing

6 outer housing of the linear piston system

8 flywheel

9 coupling element

10 diaphragm spring

12 diaphragm spring

16 cylinder attachment of the housing

18 connection area

20 connection area

22 fixing screw for connection

24 fixing screw for connection

26 mounting area

28 mounting area

30 circumferential ring

32 recess for fixing screw

40 pistons

42 cylinders

44 retaining bolts

46 coil spring

47 retaining bolts

48 chamber

50 annular gap

52 cylindrical wall

54 magnetized ring

56 magnetic coil

58 channel

60 lids

62 recess for fixing screw

Claims

claims

A balancing oscillating device (2) for a linear piston system (1), comprising a housing (4), at least two coupling members (9), and a flywheel coupled via each coupling member (9) along an axis (7) to the housing (4) (8), wherein each coupling member (9) on at least one fastening region (26, 28) on the housing (4) and on at least one connection region (18, 20) is attached to the flywheel (8),

characterized,

in that the at least one connection region (18, 20) to the flywheel (8) is radially closer to the axis (7) than the at least one attachment region (26, 28) to the housing (4), and to the at least two coupling elements (9)

that the flywheel (8) is arranged in the idle state in the axial direction between two coupling members (9).

2. balancing device (2) according to claim 1,

characterized,

that the flywheel (8) in a plane perpendicular to the axis (7) is connected substantially rigid.

3. balancing device (2) according to claim 1 or claim 2,

characterized,

that each connection region (18, 20) of a coupling element (9) to the flywheel (8) is radially closer to the axis (7) than each attachment region (26, 28) of the corresponding coupling element (9) to the housing (4).

4. balancing device (2) according to one of the preceding claims,

characterized,

in that each coupling member (9) is designed as an elastic spring element (10, 12) which is elastic in the axial direction.

5. balancing device (2) according to one of the preceding claims,

characterized, in that each coupling member (9) is connected to the or each connection area (18, 20) by welding and / or screwing and / or gluing and / or clamping, in particular by means of elastic prestressing, to the flywheel mass (8) and / or to the or each one Fixing portion (26, 28) by welding and / or screws and / or gluing and / or terminals in particular by means of elastic bias on the housing (4) is attached.

6. balancing device (2) according to one of the preceding claims,

characterized,

that the housing (4) and / or the flywheel (8) are formed substantially rotationally symmetrical.

7. balancing device (2) according to claim 6,

characterized,

the axial length of the flywheel mass (8) decreases monotonically with increasing radial distance from the axis (7).

8. balancing device (2) according to one of the preceding claims,

characterized,

that each coupling member (9) is substantially rotationally symmetrical.

9. balancing device (2) according to any one of the preceding claims,

characterized,

that each coupling member (9) in the idle state of the flywheel (8) in the radial direction of the housing (4) couples.

10. balancing device (2) according to any one of the preceding claims,

characterized,

in that the flywheel mass (8) is surrounded in the radial direction by the housing (6), and in that the housing (6) is closed off in an axial direction by a cover (60).

11. Linear piston system (1), with a linearly movably mounted piston (40) and a compensating vibration device (2) according to one of the preceding claims.

12. Linear piston system (1) according to claim 1 1,

characterized,

that the piston (40) in the housing (6) is mounted movably mounted in the axial direction.

13. linear piston system (1) according to claim 10 or claim 11,

characterized,

the piston (40) in the housing (6) is designed as a working piston of a compressor.